PR 58148 patch

[Paolo Carlini]

Hi,

On 08/29/2013 09:37 PM, François Dumont wrote:
> Indeed, I check the Standard about const_pointer, so here is another 
> attempt.
>
> Tested under Linux x86_64.
>
> 2013-08-29  François Dumont  <fdumont@gcc.gnu.org>
>
>     PR libstdc++/58148
>     * include/debug/functions.h (__foreign_iterator_aux4): Use
>     sequence const_pointer as common type to compare pointers. Add a
>     fallback overload in case pointers cannot be cast to sequence
>     const_pointer.
>     * testsuite/23_containers/vector/modifiers/insert/58148.cc: New.
>
> Ok to commit ?
Seems pretty good to me. I have been thinking: when the non-trivial 
__foreign_iterator_aux4 is selected it actually has available as the 
last two arguments

     std::addressof(*(__it._M_get_sequence()->_M_base().begin()))
     std::addressof(*__other)

we could as well give the parameters names and avoid passing __other. 
Also, I think we can do everything with std::less. I'm attaching below 
something I quickly hacked, untested, see if you like it in case commit 
something similar.

Thanks!
Paolo.

//////////////////////
-------------- next part --------------
Index: functions.h
===================================================================
--- functions.h	(revision 202068)
+++ functions.h	(working copy)
@@ -36,7 +36,7 @@
 #include <bits/move.h>                    // for __addressof and addressof
 #if __cplusplus >= 201103L
 # include <bits/stl_function.h>		  // for less and greater_equal
-# include <type_traits>			  // for common_type
+# include <type_traits>			  // for is_lvalue_reference and __and_
 #endif
 #include <debug/formatter.h>
 
@@ -172,27 +172,28 @@
     }
 
 #if __cplusplus >= 201103L
-  template<typename _Iterator, typename _Sequence,
-	   typename _InputIterator,
-	   typename _PointerType1,
-	   typename _PointerType2>
+  // Default implementation.
+  template<typename _Iterator, typename _Sequence>
     inline bool
     __foreign_iterator_aux4(const _Safe_iterator<_Iterator, _Sequence>& __it,
-			    _InputIterator __other,
-			    _PointerType1, _PointerType2)
+			    typename _Sequence::const_pointer __begin,
+			    typename _Sequence::const_pointer __other)
     {
-      typedef typename std::common_type<_PointerType1,
-					_PointerType2>::type _PointerType;
+      typedef typename _Sequence::const_pointer _PointerType;
       constexpr std::less<_PointerType> __l{};
-      constexpr std::greater_equal<_PointerType> __ge{};
 
-      return (__l(std::addressof(*__other),
-		  std::addressof(*(__it._M_get_sequence()->_M_base().begin())))
-	      || __ge(std::addressof(*__other),
-		      std::addressof(*(__it._M_get_sequence()->_M_base().end()
-				       - 1)) + 1));
+      return (__l(__other, __begin)
+	      || __l(std::addressof(*(__it._M_get_sequence()->_M_base().end()
+				      - 1)), __other));
     }
-			  
+
+  // Fallback when address type cannot be implicitely casted to sequence
+  // const_pointer.
+  template<typename _Iterator, typename _Sequence>
+    inline bool
+    __foreign_iterator_aux4(const _Safe_iterator<_Iterator, _Sequence>&, ...)
+    { return true; }
+
   template<typename _Iterator, typename _Sequence, typename _InputIterator>
     inline bool
     __foreign_iterator_aux3(const _Safe_iterator<_Iterator, _Sequence>& __it,
@@ -209,12 +210,12 @@
 	    - std::addressof(*(__it._M_get_sequence()->_M_base().begin()))
 	    == __it._M_get_sequence()->size() - 1)
 	  return (__foreign_iterator_aux4
-		  (__it, __other,
+		  (__it,
 		   std::addressof(*(__it._M_get_sequence()->_M_base().begin())),
 		   std::addressof(*__other)));
       return true;
     }
-			   
+   
   /* Fallback overload for which we can't say, assume it is valid. */
   template<typename _Iterator, typename _Sequence, typename _InputIterator>
     inline bool
@@ -223,7 +224,7 @@
 			    std::false_type)
     { return true; }
 #endif
-			   
+
   /** Checks that iterators do not belong to the same sequence. */
   template<typename _Iterator, typename _Sequence, typename _OtherIterator>
     inline bool